Being new to battery power I have been reading up one batteries and would like LSC members thoughts on preference of ion batteries compared to lipo batteries and why. Thanks, Bill
Bill Barnwell said:
Being new to battery power I have been reading up one batteries and would like LSC members thoughts on preference of ion batteries compared to lipo batteries and why. Thanks, Bill
Bill, my understanding is that LiPo batteries are just LiIon batteries in a different format (i.e. flat and rectangular to fit a laptop.)
So I googled your question and I stand (mildly) corrected:
“Lithium Ion Batteries have high energy-densities and cost less than lithium-polymer batteries. In addition, they do not require priming when first used and have a low self-discharge. However, lithium-ion batteries do suffer from aging – even when not in use. Varies, depending on electrolyte”
My pal as a LiPo battery in one of his locos and it does not seem to exhibit any different characteristics than his LiIon. Personally, I stick to LiIon for practical reasons - they come in fixed shapes (e.g. 18650 type), can be mounted in a battery box, and monitor/protection PC boards are easy to come by.
Interesting, I have not seen any credible statement that li-ion ages and li-po does not.
For our hobby, li-ion is usually found in cylindrical cells, and li-po is usually in a rectangular, somewhat flexible “pouch”… mechanical damage can result in fires, and the pouch is more easily damaged, so people typically recommend the li-ion in the “tougher” package.
Bill, inferring from your builds, I think you should stick to combinations of the 18650 cells for your best price/performance. Not as space-efficient as the prismatic (rectangular) li-po, but usually a better choice in our hobby.
Greg
Greg, thanks for the reply, I was more concerned about safety than anything else but the more I have read lipo seems to get a bad rap for bad chargers, and you are right about size. Right now I’m looking at a ion that is only 3.14" x 2.75" x .78" which I might be able to fit in my tender section of my Mason Bogie and although it is only 3400 mah it might work with the small size of the gscale graphics railboss board and then it would all be onboard without having to use a trailing car, Thanks, Bill
it’s not really the chargers, it’s physical damage to the pack that causes the most problems.
On chargers, get one that is set for your voltage and works with the amp hours. I prefer chargers that can be configured for different packs, but it’s easy to make a mistake and charge wrong.
Also, I don’t really see the need for balancing chargers, we do not work our batteries hard like the airplane guys.
Greg
Either cell type, utilizes the same charger and charging algorithm with some caveats and require like care. Both cell types suffer from similar aging and or life cycles; generally the application, care and feeding dictate lifespan as well as the quality of the materials and assembly processes. My experience with thousands of lithium batteries suggests that they have similar life span cycles. Either cell types inherently have low self-discharge and do NOT require “priming”. Lastly the life cycle clock starts as soon as the cells are assembled, used, stored and ignored matters not.
I predominantly use Li-Po batteries for trains, planes, drones and RC cars/trucks and have realized zero pouch failures to date. There are many Li-Po batteries sold/equipped with plastic hard case shells to protect said pouches. Battery protection circuit boards with desirable additional features are readily available for Li-Po’s if so desired. I use SMART balance charger features with both cell types and find it very informative (I assemble Li-Ion batteries and add balance charge pigtails to same).
Li-Po’s batteries are generally speaking much cheaper as compared to Li-Ion batteries of like capacity and voltages.
I believe Lithium catastrophic battery failure modes are generally the FAULT of the operators interaction with the charger in play, the WRONG charger and or poor integration of said batteries. Dedicated use simple chargers (cell count/voltage specific) without the ability to change charging parameters provide a safer approach as compared to programable chargers.
Michael
Will a 18.5 battery out last a 14.8 if both batteries are of the same mah, run the same engine at the same speed? Is it smart to purchase higher voltage batteries?
Bill Barnwell said:
Will a 18.5 battery out last a 14.8 if both batteries are of the same mah, run the same engine at the same speed? Is it smart to purchase higher voltage batteries?
Bill, to run an engine at a specific speed requires a specific voltage, and that dictates what current (amps) the motor draws. So if the engine is running at the same speed and the batteries have the same capacity to produce amps (milliampere-hours, or “mah”,) then the maximum voltage is irrelevant. The max allows your train to run faster, buit if the ‘mah’ are the same, it won’t run any longer.
That’s my story until someone who understands this stuff properly jumps in.
Not an EE by any stretch but ohms law comes into play here, so voltage is a factor in all this.
I think that higher voltage in NIMH in the packs I use extend the operational life (2600mah 19.6v) lasts me better than three hours in a switching scenario.
now another factor are you running continuously at speed, or are you switching an area, then running to the next switching area.
the discharge characteristics will also come to play with how they are used to yield your total run time.
Al P.
Bill Barnwell said:
Will a 18.5 battery out last a 14.8 if both batteries are of the same mah, run the same engine at the same speed? Is it smart to purchase higher voltage batteries?
To be accurate, all other things the same, yes, the higher voltage battery will outlast, because you are not using it as much, for the same run time, you will discharge less, and have to recharge less, so theoretically you will have fewer charge/discharge cycles and thus that battery will last longer.
How much difference will it make, I would opine that not much. If I ran steamers with lower prototype speeds than my mainline class 1 stuff, I would pick the lower voltage batteries and increase the capacity. Then you would get longer run time and ostensibly longer life.
I would not go lower voltage since most sound cards are DCC and do not like much lower voltages, can’t get too close to 12v.
Greg
Greg, Al and Pete, thanks for your input